1. Field of the Invention
The present invention relates generally to disk drives, and more particularly to a method of assembling a disk drive while electrically grounding a disk drive cover.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA). The spindle motor includes a spindle motor hub that is rotatably attached to the disk drive base. The hub has an outer hub flange that supports a lowermost one of the disks. Additional disks may be stacked and separated with annular disk spacers that are disposed about the hub. The head stack assembly has an actuator assembly having at least one transducer head, typically several, for reading and writing data to and from the disk. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to the generated servo control signals from the disk controller. In so doing, the attached heads are moved relative to tracks disposed upon the disk.
The head stack assembly includes an actuator assembly, at least one head gimbal assembly, and a flex circuit cable assembly. A conventional “rotary” or “swing-type” actuator assembly typically comprises an actuator body that rotates on a pivot assembly between limited positions, a coil portion that extends from one side of the actuator body to interact with one or more permanent magnets to form a voice coil motor, and one or more actuator arms which that extend from an opposite side of the actuator body. A head gimbal assembly includes a head which is distally attached to each of the actuator arms. The actuator assembly includes the actuator body that has a bore and a pivot bearing cartridge engaged within the bore. The head gimbal assembly and the flex circuit cable assembly are attached to the actuator assembly.
A plurality of fasteners, such as metal screws, are disposed about a periphery of the disk drive cover and engage the periphery of the disk drive base for attachment of the disk drive cover with the disk drive base. Typically, a fastener is engaged to the pivot bearing cartridge through the disk drive cover, and another fastener is engaged to the spindle motor also through the disk drive cover.
For any number of reasons, it may be desirable to provide a coating, such as E-coating, about the surface of the disk drive cover. For example, the coating may be utilized as a corrosion barrier for protecting the disk drive cover.
A problem that is introduced with the application of such a coating upon the disk drive cover is that the coated disk drive cover may become electrically insulated from other portions of the disk drive, because the coating tends to be electrically insulative in nature. In the absence of the coating, the disk drive cover is typically in direct electrical contact with a grounded portion of a fixture utilized to support the disk drive cover during assembly of the disk drive cover to the disk drive base thereby grounding the disk drive cover. On the coated disk drive cover, however, a static electric charge may be built up on the surface of the coated disk drive cover. Unless removed, this static electric charge creates a high voltage potential between the disk drive cover and the other portions of the disk drive that may discharge to any number of the components within the disk drive, such as the transducers. Such a discharge may damage the disk drive components.
Accordingly, there is a need in the art for an improved method of assembling the disk drive and in particular grounding the disk drive cover during the attachment process in comparison to the prior art.